This invention relates to machines for forming envelopes and more particularly to assemblies or combinations of high speed blank cutting units, envelope folding machines, and associated conveyors which interconnect the units and assure that envelope blanks are transported to the folder unit in proper positional relation. This invention permits the mating of known high speed cutters and known rotary folding machines to obtain assemblies and operating flexibilities and advantages not heretofore available.
In modern envelope operations, different units which perform separate functions are frequently combined to form a single machine capable of performing a number of functions in one continuous operation. More specifically, it is frequently advantageous to combine a high speed, continuous paper web blank cutting unit with an envelope forming or folding unit which has no blank cutting capability. This alleviates the time consuming and wasteful need for die cutting envelope blanks from sheets of paper and manually stacking the blanks in position for entry into the envelope forming unit. In addition, such a combination allows for the continued use of pre-existing folding machines, which are very complex and expensive, while thereby enhancing the utility and flexibility of such units. However, because some envelope folding units have their blank entry point at a position intermediate either end, it has been difficult to combine such a unit with the more desirable high speed, continuous blank cutting unit. In particular, such a link between a "High Speed Rotary Diagonal Web Attachment", model HD, and a Rotary Window Envelope Forming unit, Model RW, each manufactured by F. L. Smithe Machine Compay of Dunconsville, Pennsylvania, was not accomplished in the past apparently because of such limitations.
Simultaneously with transporting blanks to the entry point of such a mid-entry envelope forming unit, it is frequently necessary that the blanks arrive at the unit entry point within a predetermined time sequence and at a high feed rate. These requirements necessitate accurate positional maintenance of the blanks as they leave the cutting unit, travel to, and arrive at the envelope forming unit entry point. While assuring positional blank relation along the conveyor path, path direction modification must be accomplished without wrinkling, scuffing or otherwise marring the envelope blanks.
To achieve the cutting of blanks and forming of envelopes in a high speed environment, accurate coordination of the cycling of such joined units must be achieved. As such, the operation of an envelope conveyor for interconnecting or "marrying" cutting and forming units must be coordinated with both units being interconnected.